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Test method of high-temp, component creep life

A technology of creep life and test method, which is applied in the direction of applying stable tension/pressure to test the strength of materials, and can solve problems such as errors, amplification, and low reliability of life evaluation results

Inactive Publication Date: 2004-02-25
XIAN THERMAL POWER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] 2. With the continuous service at high temperature, the creep failure resistance of the same material will change significantly
However, this model does not take into account the aging process of component materials, which leads to serious defects and errors in the results of this method when evaluating the life of long-term service components. The results obtained by using the traditional L-M method are much higher than the real life of components. , such as the actual service life of superheater tubes in power plants is often much lower than the results of theoretical calculations
Since the aging state of the material has not been considered, the safety factor can only be passively used for correction, and the most suitable safety factor is uncertain, so the influence of human factors is greatly amplified, and the predicted results must be significantly different from the actual ones. The uncertainty of this error directly leads to the consequence of low reliability of life assessment results

Method used

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  • Test method of high-temp, component creep life
  • Test method of high-temp, component creep life
  • Test method of high-temp, component creep life

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] Using a unified idea and simulation method, the typical curves and relational expressions of the aging factor correction method for various boiler materials and steam turbine materials are given. figure 1 The characteristic curve of the aging factor Ca of 12Cr1MoV steel commonly used in power plant boilers gradually decreases with the change of service stress and temperature-time state is given, in which the abscissa is the LMP parameter, and the ordinate is the logarithmic stress.

[0020] Select 12Cr1MoV steel pipe samples with different aging degrees obtained after actual use, and first use the quantitative aging degree test method to evaluate the aging degree of each pipe sample. The aging degree of the unused new material is zero, and the aging degree of the creep failure pipe sample is 100%.

[0021] For samples of each aging degree, the variable stress simulation test is carried out at a constant temperature T and the variable temperature simulation test is carri...

Embodiment 2

[0026] The target is a high-temperature superheater component that has been used for 80,000 hours in a power plant and has been seriously aged. Due to the difference in the use environment, the aging degree of the 34 superheater tubes in the tube row is significantly different, resulting in a significant difference in the remaining life.

[0027] The invention is used to quantitatively evaluate the aging degree of each superheater tube; the indirect evaluation method of the metal wall temperature of the boiler tube is used to quantitatively evaluate the equivalent temperature of the metal wall temperature of each superheater tube; the circumferential stress of the boiler tube is used to calculate method, quantitatively evaluate the actual circumferential stress of each superheater tube.

[0028] The residual life of the same pipe row was evaluated by two new and old methods respectively, and the results are shown in image 3 .

[0029] It can be seen from the results that, us...

Embodiment 3

[0033] In November 2002, the residual life of the convection superheater of the No. 2 boiler of Huaneng Huaiyin Power Plant was evaluated by using the aging factor correction method. The basic method is the same as above.

[0034] Among them, the life evaluation results of 84 tubes in the lower elbow part of the hot section of the superheater are as follows: Figure 4 shown. It can be seen from the results that after 60,000 hours of actual use, the residual life of some pipe sections is less than 20,000 hours, and the remaining life of individual pipes is only a few thousand hours, so they must be replaced as soon as possible. The power plant adopted this suggestion and has replaced the hot section of the superheater as a whole to ensure the reliability of equipment operation.

[0035] The abscissa in the figure is the number of 1 to 84 pipes, and the ordinate is the result of the remaining life (hours) corresponding to each pipe calculated and evaluated.

[0036] The actual...

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Abstract

The testing method of high-temp. component creep life adopts the simulation pipe-bursting test machine or durable strength testing machine to make creep rupture acceleration simulation test of new materials which have different ageing extents and are not aged under the condition of a series of temp. and stresses. It adopts polynomical regressive analysis method to process data, and obtain the relationship formula of non-aged material between ageing factor, temp. and life time. By utilizing test, data processing and formula operation the material creep service life can be obtained.

Description

1. Technical field [0001] The invention relates to a method for testing the creep life of parts used in a power plant under high temperature. 2. Background technology [0002] Research in recent years has found that after long-term high-temperature service, the service status of power plant components will generally change significantly. This change is mainly manifested in two aspects: the decline of macroscopic strength and the aging and damage of microstructure, which are typical types of aging characteristics. ; When the macroscopic strength drops to a certain critical value, creep cracking failure due to insufficient strength is the main failure mode of high-temperature components; the decline of macroscopic strength is generally directly related to the change of the microstructure of the material, and the research on the relationship is One of the main contents of power plant materials science; these two types of aging characteristics are directly related to state param...

Claims

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Application Information

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IPC IPC(8): G01N3/08G01N3/18
Inventor 李耀君
Owner XIAN THERMAL POWER RES INST CO LTD
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